Improving numerical reasoning capabilities of inductive logic programming systems

Inductive Logic Programming (ILP) systems have been largely applied to classification problems with a considerable success. The use of ILP systems in problems requiring numerical reasoning capabilities has been far less successful. Current systems have very limited numerical reasoning capabilities, which limits the range of domains where the ILP paradigm may be applied. This paper proposes improvements in numerical reasoning capabilities of ILP systems. It proposes the use of statistical-based techniques like Model Validation and Model Selection to improve noise handling and it introduces a new search stopping criterium based on the PAG method to evaluate learning performance. We have found these extensions essential to improve on results mer statistical-based algorithms for time series forecasting used in the empirical evaluation study

Towards meta-interpretive learning of programming language semantics

We introduce a new application for inductive logic programming: learning the semantics of programming languages from example evaluations. In this short paper, we explored a simplified task in this domain using the Metagol meta-interpretive learning system. We highlighted the challenging aspects of this scenario, including abstracting over function symbols, nonterminating examples, and learning non-observed predicates, and proposed extensions to Metagol helpful for overcoming these challenges, which may prove useful in other domains.Comment: ILP 2019, to appea

Inductive learning spatial attention

This paper investigates the automatic induction of spatial attention from the visual observation of objects manipulated on a table top. In this work, space is represented in terms of a novel observer-object relative reference system, named Local Cardinal System, defined upon the local neighbourhood of objects on the table. We present results of applying the proposed methodology on five distinct scenarios involving the construction of spatial patterns of coloured blocks

Ultra-Strong Machine Learning: comprehensibility of programs learned with ILP

During the 1980s Michie defined Machine Learning in terms of two orthogonal axes of performance: predictive accuracy and comprehensibility of generated hypotheses. Since predictive accuracy was readily measurable and comprehensibility not so, later definitions in the 1990s, such as Mitchell’s, tended to use a one-dimensional approach to Machine Learning based solely on predictive accuracy, ultimately favouring statistical over symbolic Machine Learning approaches. In this paper we provide a definition of comprehensibility of hypotheses which can be estimated using human participant trials. We present two sets of experiments testing human comprehensibility of logic programs. In the first experiment we test human comprehensibility with and without predicate invention. Results indicate comprehensibility is affected not only by the complexity of the presented program but also by the existence of anonymous predicate symbols. In the second experiment we directly test whether any state-of-the-art ILP systems are ultra-strong learners in Michie’s sense, and select the Metagol system for use in humans trials. Results show participants were not able to learn the relational concept on their own from a set of examples but they were able to apply the relational definition provided by the ILP system correctly. This implies the existence of a class of relational concepts which are hard to acquire for humans, though easy to understand given an abstract explanation. We believe improved understanding of this class could have potential relevance to contexts involving human learning, teaching and verbal interaction

Wavenumber prediction and measurement of axisymmetric waves in buried fluid-filled pipes: Inclusion of shear coupling at a lubricated pipe/soil interface

Acoustic methods have been widely used to detect water leaks in buried fluid-filled pipes, and these technologies also have the potential to locate buried pipes and cables. Relatively predictable for metal pipes, there is considerably more uncertainty with plastic pipes, as the wave propagation behaviour becomes highly coupled between the pipe wall, the contained fluid and surrounding medium. Based on the fully three-dimensional effect of the surrounding soil, pipe equations for n=0 axisymmetric wave motion are derived for a buried, fluid-filled pipe. The characteristics of propagation and attenuation are analysed for two n=0 waves, the s=1 wave and s=2 wave, which correspond to a predominantly fluid-borne wave and a compressional wave predominantly in the shell, respectively. At the pipe/soil interface, two extreme cases may be considered in order to investigate the effects of shear coupling: the “slip” condition representing lubricated contact; and the “no slip” condition representing compact contact. Here, the “slip” case is considered, for which, at low frequencies, analytical expressions can be derived for the two wavenumbers, corresponding to the s=1 and s=2 waves. These are both then compared with the situations in which there is no surrounding soil and in which the pipe is surrounded by fluid only, which cannot support shear. It is found that the predominant effect of shear at the pipe/soil interface is to add stiffness along with damping due to radiation. For the fluid-dominated wave, this causes the wavespeed to increase and increases the wave attenuation. For the shell-dominated wave there is little effect on the wavespeed but a marked increase in wave attenuation. Comparison with experimental measurements confirms the theoretical finding

Diversity, urban space and the right to the provincial city

Using three vignettes of the same physical space this article contributes to understanding of how the right to the city is contested in provincial England in the early twenty-first century. Oral history and ethnographic material gathered in Peterborough between 2010 and 2012 are drawn on to shed new light on the politics of diversity and urban space. This highlights the multiple place attachments and trans-spatial practices of all residents, including the white ethnic majority, as well as contrasting forms of active intervention in space with their different temporalities and affective intensities. The article carries its own diversity politics, seeking to reduce the harm done by racism through challenging the normalisation of the idea of a local, indigenous population, left out by multiculturalism. It simultaneously raises critical questions about capitalist regeneration strategies in terms of their impact both on class inequality and on the environment

QuickSpec: Guessing Formal Specifications using Testing

We present QuickSpec, a tool that automatically generates algebraic specifications for sets of pure functions. The tool is based on testing, rather than static analysis or theorem proving. The main challenge QuickSpec faces is to keep the number of generated equations to a minimum while maintaining completeness. We demonstrate how QuickSpec can improve one’s understanding of a program module by exploring the laws that are generated using two case studies: a heap library for Haskell and a fixed-point arithmetic library for Erlang